The invention pertains to control and, more particularly, to methods and apparatus for configuring control systems.
The terms xe2x80x9ccontrolxe2x80x9d and xe2x80x9ccontrol systemsxe2x80x9d refer to the control of a device, process or system by monitoring one or more of its characteristics. This is used to insure that output, processing, quality and/or efficiency remain within desired parameters over the course of time. In many control systems, digital data processing or other automated apparatus monitor a device, process or system and automatically adjust its operational parameters. In other control systems, such apparatus monitor the device, process or system and display alarms or other indicia of its characteristics, leaving responsibility for adjustment to the operator.
Control is used in a number of fields. Process control, for example, is typically employed in the manufacturing sector for process, repetitive and discrete manufactures, though, it also has wide application in utility and other service industries. Environmental control finds application in residential, commercial, institutional and industrial settings, where temperature and other environmental factors must be properly maintained. Control is also used in articles of manufacture, from toasters to aircraft, to monitor and control device operation.
Modern day control systems typically include a combination of field devices, control devices, and controllers, the functions of which may overlap or be combined. Field devices include temperature, flow and other sensors that measure characteristics of the device, process or system being controlled. Control devices include valves, actuators, and the like, that control the device, process or system itself.
Controllers generate settings for the control devices based on measurements from the field devices. Controller operation is typically based on a xe2x80x9ccontrol algorithmxe2x80x9d that maintains a controlled system at a desired level, or drives it to that level, by minimizing differences between the values measured by the sensors and, for example, a setpoint defined by the operator.
In a food processing plant, for example, a controller can be used to maintain soup stock at a simmer or low boil. This is done by comparing measurements of vapor pressure in the processing vessel with a desired set-point. If the vessel pressure is too low, the control algorithm may call for incrementally opening the heating gas valves, thereby, driving the pressure and boiling activity upwards. As the pressure approaches the desired set-point, the algorithm requires incrementally leveling the valves to maintain the roil of the boil.
Controllers may be networked or otherwise connected to other computing apparatus that facilitate monitoring or administration. The so-called S88 industry standard, described in Batch Controlxe2x80x94Part 1: Models and Terminology (The International Society for Measurement and Control 1995), for example, defines a hierarchy of processing and control equipment (xe2x80x9cequipment entitiesxe2x80x9d) that can be used to model and control an automated manufacturing process. At the lowest level of the hierarchy are control modules that directly manipulate field devices (e.g., opening and closing valves and, possibly, other control modules. At a higher level, equipment modules coordinate the functions control modules, as well as of other equipment modules, and may execute phases of the manufacturing process (such as setting controller constants and modes). xe2x80x9cUnits,xe2x80x9d at still a higher level of the hierarchy, coordinate the functions of equipment and control modules. Process cells orchestrate all processing activities required to produce a manufacturing batch, e.g., scheduling, preparing and monitoring equipment or resources, and so forth.
The principal function of controllers is executing control algorithms for the real-time monitoring and control of devices, processes or systems. They typically have neither the computing power nor user interfaces required to facilitate the design of a control algorithm. Instead, the art has developed configurators. These are typically general purpose computers (e.g., workstations) running software that permit an engineer or operator to graphically model a device, process or system and the desired strategy for controlling it. This includes enumerating field devices, control devices, controllers and other apparatus that will be used for control, specifying their interrelationships and the information that will be transferred among them, as well as detailing the calculations and methodology they will apply for purposes of control. Once modeling is complete and tested, the control algorithm is downloaded to the controllers.
One well known process control system configurator is that provided with the I/A Series(copyright) (hereinafter, xe2x80x9cIASxe2x80x9d or xe2x80x9cI/Axe2x80x9d) systems, marketed by the assignee hereof These provide a graphical interface (FoxCAE) permitting an engineer to model a process hierarchically and to define a control algorithm from that hierarchy. Multiple editors are provided for defining and modifying modules within the hierarchy.
Though prior art process control configuration systems, particularly, the IAS systems and others sold by the assignee hereof, have met wide acceptance in the industry, there remains room for improvement. Such is the case, for example, with respect to the configuration of complex control systems.
In this context, an object of the present invention is to provide improved methods and apparatus for control and, particularly, for configuring control systems. A related object of the invention is to provide methods and apparatus for configuring process control systems.
A further object of the invention is to provide such methods and apparatus as facilitate configuring large or complex control systems
Still yet a further object of the invention is to provide such methods and apparatus as can be used in configuring a range of control systems, whether hierarchical or not, whether pertaining to process control or otherwise.
The foregoing objects are among those attained by the invention which provides, in one aspect, improved apparatus for configuring process, environmental, industrial and other control systems. Such apparatus employ xe2x80x9cappearancexe2x80x9d objects (or other data and/or programming constructs) defining the appearance of configurable system components in graphical editors or other views in which the components may be depicted. xe2x80x9cPlaceholderxe2x80x9d objects (or other constructs) persist the location, size, color, or other aspects of appearance defined by an appearance object in displays, reports, depictions, presentations and other view (collectively, hereinafter, xe2x80x9cviewsxe2x80x9d) in which the corresponding configurable component is actually depicted.
By way of example, a process control configuration apparatus according to this aspect of the invention uses xe2x80x9cconfigurablexe2x80x9d objects to define blocks, loops and other components of a process control system. Appearance objects provide (or reference) icons or representations indicating how the configurable objects are to be depicted, e.g., in a configuration editor. Placeholder objects are created for each configurable object that is placed in a configuration using that editor.
The placeholder objects identify the sizes, locations, colors, etc., of the icons used in the editor to represent the configurable objects.
Further aspects of the invention provide a configuration apparatus as described above in which the appearance objects identify labels or other textual information, e.g., configurable object names or types, for display with icons or other appearance indictors in the appearance objects. According to related aspects of the invention, those labels, as well as the icons themselves, can be specified using macros. Thus, for example, an appearance object can include macro strings, such as xe2x80x9c$NAMExe2x80x9d, xe2x80x9c$TYPExe2x80x9d, xe2x80x9c$ICONxe2x80x9d, that are replaced subsequent to configuration, e.g., with a configurable object name, type and icon, respectively.
The invention provides, in other aspects, apparatus as described above in which each configurable object has one or more parameters that identify the appearance of that object in views in which it may appear. The parameters may refer to appearance objects (or other constructs) as described above or they may contain appearance information (e.g., icons and textual identifiers) themselves.
The configurable objects of such an apparatus can be associated with one another in a hierarchical relationship, such that at least one such object is a descendant of another. Descendants, according to this aspect of the invention, inherit parameters from their ancestors. Accordingly, icons or other appearance information identified in a xe2x80x9cparentxe2x80x9d configuration object is passed on to its children. Inherited information may be overridden, according to aspects of the invention.
Still further aspects of the invention provide apparatus as described above comprising persistent documents that contain placeholder objects. Each persistent document may represent a specific configuration, e.g., created by a specific editor and displayed in accord with a selected view. Thus, for example, the configuration of a process control system may be represented in several documents, each edited by control algorithm diagram editor, covering different portions of the system.
In addition to placeholder objects, the persistent document may contain connector graphics that depict relationships between configurable objects. In an apparatus used for configuring process control systems, such a graphic may indicate, for example, that one configurable object, e.g., representing an analog input block, is a source for another configurable object, e.g., representing a PID controller. Such connector graphics can represent peer-to-peer relationships (such as source/sink relationships), in addition to hierarchical relationships (such as parent/child relationships).
Further aspects of the invention provide apparatus as described above for configuring process control systems. In such apparatus, configurable objects can, for example, represent entities within any of (i) a controlled process, (ii) the process control system, (iii) the apparatus for configuring the process control system, (iv) a level in a control level hierarchy, such as the aforementioned S88 standard. Such entities include, by way of non-limiting example, field devices, control processors, blocks, loops, compounds, historians, object type category, display placeholders, graphical display entities, and reports.
Still further aspects of the invention provide methods paralleling the apparatus described above.
These and other aspects of the invention are evident in the drawings, the claims, and in the detailed description that follows.